VALIDATION OF QUANTITATIVE CHROMATOGRAPHIC ANALYSIS ON LABORATORY-PREPARED THIN-LAYERS

Validation of the determination of amino acids on laboratory-prepared plates was performed on a mixed natural zeolite and microcrystalline cellulose sorbent. Chromatograms were recorded in the visible region using a Datacolor DC 3890 reflectance spectrometer, Camag Turner Fluorimeter 111 slit-scanning densitometer and Leco 2001 image analyser. The precision, detection limit and limit of quantification for each method were determined. A lower total R.S.D. was obtained by measuring colour remission with the Datacolor system (2.7% for high concentration and 3% for low concentration), with an instrumental R.S.D. of 0.1-0.2%. Densitometry and image analysis resulted in a lower precision, especially at low concentration (total R.S.D.>10%), with a significant instrumental error.